1. Field of the Invention
Example embodiments of the present invention relate to an image forming apparatus such as an inkjet recording apparatus, an image forming method, and a recording medium storing a program that causes the apparatus to execute the method.
2. Description of the Background
Image forming apparatuses are used as printers, facsimile machines, copiers, and multi-functional devices combining several of the foregoing capabilities. As one of such image forming apparatuses, an inkjet recording apparatus is known that employs a liquid-ejection recording method in which the apparatus performs image formation (hereinafter, recording, printing, and imaging are used as synonyms thereof) by ejecting droplets of ink from a recording head onto a recording medium or sheet.
Such an inkjet image forming apparatus also performs maintenance on the recording head to maintain the recording head in good condition. However, such maintenance consumes a relatively large amount of ink, in fact, more ink than is required for printing.
Consequently, it can happen that maintenance may not be executed even though a sufficient amount of ink required for printing remains in a given ink cartridge. In such a case, the ink cartridge is deemed to be empty or nearly empty of ink, processed as a near-empty or empty error, and rendered unusable. Further, an alert is displayed to prompt a user to replace the ink cartridge.
When, for example, an ink near-empty or empty error occurs in a first one of a plurality of ink cartridges, one conventional inkjet image forming apparatus compares the amount of ink required to execute a cartridge replacement sequence to the amount of ink remaining in each of the other ink cartridges. If the amount of ink remaining in any second one of the other ink cartridges is less than the required ink amount, the apparatus processes the second ink cartridge as the ink near-empty or empty error.
However, the conventional processing of such an ink near-empty or empty error may have the following disadvantages.
For example, the amount of ink consumed in cartridge replacement is in fact selected from among a plurality of different cartridge replacement sequences depending on the condition of the recording head or the apparatus. Therefore, since what is considered to be the necessary minimum amount of ink remaining in each of the ink cartridges varies depending on the type of selected cartridge replacement sequence, it may be impossible to determine a single threshold applicable to all the ink cartridges when simultaneously prompting the replacement of a plurality of ink cartridges.
Also, when an ink empty error occurs in one of the plurality of ink cartridges, an ink cartridge in which less ink than a threshold amount remains is processed as an ink near-empty or empty error, and processing for rendering the cartridge unusable is executed. Consequently, such an ink cartridge in which a sufficient amount of ink for printing still remains (but not enough ink for maintenance) may nevertheless be rendered unusable anyway, inadvertently resulting in waste of ink.